Can anyone kindly explain in simple terms how anthropologists use teeth and bone to determine age?

In simple terms, these calcium-dense parts of the human body are often the only remains to study in anthropologic digs. Because bones and teeth accumulate matter as a person grows through life stages (as opposed to softer organs, etc.), the very size—length and circumference—of a bone can determine, on a scale from infancy (where the bone is still soft and small) to old age (where the bones are brittle, even porous), the approximate age at...

In simple terms, these calcium-dense parts of the human body are often the only remains to study in anthropologic digs. Because bones and teeth accumulate matter as a person grows through life stages (as opposed to softer organs, etc.), the very size—length and circumference—of a bone can determine, on a scale from infancy (where the bone is still soft and small) to old age (where the bones are brittle, even porous), the approximate age at death can be estimated. Further, the social status can sometimes be determined, if the bone bears marks of healing after combat, for example. Teeth are equally revealing—the amount of wear, and the size, and in some cases, the presence of wisdom teeth, for example, can all help determine age, and therefore more about the archeological site itself. All these are field clues: when the remains are taken back to the lab, microanalysis can give clues to diet, health, even cause of death. The anthropologist takes this information, together with other artifacts and geological clues, and by inference and inductive reasoning, builds a picture of what civilization he/she is studying.